Date:	Sunday 26 October 1986
Time:	20:00
Type:	Airbus A300B4-601
Owner/operator:	Thai Airways International
Registration:	HS-TAE
MSN:	395
Year of manufacture:	1986
Total airframe hrs:	135 hours
Cycles:	45 flights
Engine model:	General Electric CF6-80C2A1
Fatalities:	Fatalities: 0 / Occupants: 239
Aircraft damage:	Substantial, repaired
Category:	UI
Location:	over Tosa Bay -   Japan
Phase:	En route
Nature:	Passenger - Scheduled
Departure airport:	Manila International Airport (MNL/RPLL)
Destination airport:	Osaka-Itami Airport (ITM/RJOO)
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Thai Airways International Flight 620 departed Bangkok at 04:05 UTC for a flight to Osaka via Manila. The flight arrived at Manila at 07:17 and took off again after 41 minutes. The planned en route cruising speed would be 480 knots, at flight level 330 with an estimated flight time to Osaka of 3 hours and 17 minutes. The Airbus A.300 passed over Shimizu VOR 10:56 hours at flight level 330, and was cleared to descend to FL120 at 11:00. At that moment the captain was returning from the lavatory to the flight deck.
A sudden explosion occurred in the vicinity of the aft most lavatory on the left side, and the passenger cabin was brought into a rapid decompression. The captain returned to his seat and the co-pilot immediately initiated an emergency descent. During the descent Dutch roll occurred and the auto trim was inoperative. Both pilots were fighting at the controls to while several warning systems activated. The airplane descended at a rate of 12500 feet/min, exceeding the maximum operation limit speed by 10%. At about FL250 the crew attempted to level the aircraft to stabilize. This manoeuvre resulted in a maximum acceleration of +2,6 G's. The Airbus was difficult to operate due to Dutch roll. The nose rose to a 17-degree angle. The flight crew brought down the nose, after which the plane began to bank to the right.
The crew initiated a rapid descent again at a rate of 13600 feet/min, exceeding the maximum operation limit speed by 19%, pitching 20-degreees nose down. At 11:07 the crew were finally able to respond to queries from Tokyo Control. Tokyo Control continued radar navigational guidance to the aircraft and transferred radio communication of the aircraft to Osaka Approach. At 11:34 Osaka Approach cleared the plane for an instrument approach to runway 32L and transferred radio communication to Osaka Tower, which cleared the aircraft to land 11:35. The aircraft touched down at 11:40 hours.

PROBABLE CAUSE: "It is recognized that the cause of this accident was that an explosive, brought into the aircraft, blew up in the left aft lavatory."

Flight Intyernational 1.11.1986, 8.11.1986
ICAO Adrep Summary 5/88 (#2)

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